1. Field of the Invention
The present invention relates to an image forming device such as a laser printer, a multifunctional machine, a copier or the like. More particularly, the present invention relates to a cooling apparatus that directs cooling air into an image forming device to maintain suitable temperatures in the image forming device and the components such as a photoconductive body, a developing device, a jam cover, and/or an optical part of scanner therein. The invention is also directed to an image forming device having the cooling apparatus.
2. Description of the Related Art
Generally, an electrophotographic image forming device has a printer unit that prints a required image onto a recording medium such as a sheet of printing paper through a series of image forming processes. The image forming processes comprise a charging process, a light-exposing process, a developing process, a transfer process, and a fusing process.
A fusing part of the printer unit fuses and presses a developer image transferred onto the recording medium to fix the image thereon during the fixing process, thereby obtaining a required permanent image. The fusing part has a fixing roller, and a pressing roller. The fixing roller is heated by a heating source such as a halogen lamp installed therein, and the pressing roller is pressed against the fixing roller by an elastic or spring pressing device to apply a pressure to the recording medium. The fixing roller and the pressing roller are covered up by a jam cover. The jam cover is hinged, so that when a jam is generated between the fixing roller and the pressing roller, it can be opened to remove the jam.
The fixing roller is usually heated to maintain a temperature of about 165° C. during a print standby mode, and at a temperature of about 180° C. during a printing mode. Therefore, a heat which is emitted from the fixing roller may cause temperatures of components such as a photoconductivity body, a developing part and the like as well as a temperature in the image forming device to abnormally increase, thereby deteriorating a performance of the image forming device.
In particular, since the jam cover is located directly adjacent to the fixing roller, its temperature may be increased by more than about 70° C. after the recording media are continuously printed and discharged. Accordingly, when a user contacts the jam cover to remove a jam generated between the fixing roller and the pressing roller during a printing, it is possible for the user to be burned due to the jam cover heated.
Also, if the electrophotographic image forming device has a copying function as in a multifunctional machine, a copier and the like, it further comprises a scanner unit that scans a document to print or store data scanned from the document.
The scanner unit is usually disposed directly above a stack of the printer unit to which the recording medium is discharged, at the uppermost part of the image forming device. Accordingly, the scanner unit is directly subjected to a heat emitted from the fixing roller of the fusing part and the recording medium that is discharged to the stack via the fusing part. Particularly, the scanner unit is provided with optical parts such as a mirror and a lens and the like, electronic parts such as a CCD module and the like, and precision parts requiring an evenness such as a rack gear on which the CCD module is moved, and the like. Therefore, an increase in the temperature of the scanner unit results in a thermal deformation of the optical parts, the electronic parts, and the precision parts, thereby deteriorating a performance of the scanner unit.
To prevent the temperatures of the components and the jam cover of the printer unit and/or the scanner unit from increasing due to the heat from the fixing roller as described above, a blowing cooling apparatus that directs the air into the printer unit and/or the scanner unit by force may be considered to be applied to the image forming device. In this case, a fan is installed outside the printer unit to which the jam cover is located, and/or at outside the scanned unit. However, the blowing cooling apparatus is effective to decrease the temperature of the jam cover and/or the scanner unit to and/or into which the air is sent, but may cause heat from the jam cover to be transferred to peripheral parts such as the photoconductive body, the developing part and the like in the vicinity of the jam cover by the air around the jam cover, thereby increasing temperatures of the peripheral parts. The air may cause dust and the like to flow into the scanner unit through the air opening into the scanner unit, thereby contaminating the optical parts in the scanner unit. Further, in the blowing cooling apparatus, when air pressure in the printer unit and/or the scanner unit reaches a certain level, the air does not flow into the printer unit and/or the scanner unit, although the fan runs idle, thereby generating a noise.
Another method to prevent the temperatures of the components and the jam cover of the printer unit and/or the scanner unit from increasing due to the heat from the fixing roller, a discharge or suction apparatus that sends an air in the printer unit and/or the scanner unit outside the printer or scanner may be considered. In this case, a fan is installed in the printer unit in the vicinity of a portion thereof where the jam cover is located, and/or in the scanned unit. However, the discharge apparatus has a disadvantage that only the jam cover of the printer unit and/or the portion of the scanner unit to which the fan is installed is cooled, since only air in the vicinity of the jam cover of the printer unit and/or the portion of the scanner unit where the fan is installed is sent to the outside of the printer unit and/or the scanner unit. Also, in the scanner unit having the optical parts, dust and the like may flow into the scanner unit through an opening for sending the air in the scanner unit to the outside thereof, thereby contaminating the optical parts in the scanner unit to deteriorate a performance thereof.